PKA, PHO and stress response pathways regulate the expression of UDP-glucose pyrophosphorylase through Msn2/4 in budding yeast.

Ugp1, a UDP-glucose pyrophosphorylase, is essential for various cellular activities in Saccharomyces cerevisiae because its product, UDP-glucose, is a sole glucosyl donor in several metabolic pathways. Here, we report that Msn2/4 play a crucial role in the regulation of UGP1 expression. Msn2/4 bound to three stress response elements in the UGP1 promoter in a protein kinase A (PKA)-dependent manner. Several stresses induced UGP1 transcription, suggesting that the regulation of UGP1 mediated by Msn2/4 is involved in general stress response. Furthermore, the phosphate response (PHO) pathway also controlled Msn2/4-dependent regulation of UGP1, providing a novel link between the PKA and PHO pathways. Our data suggest that signals of the PKA, PHO and stress response pathways regulate UGP1 expression via Msn2/4 in S. cerevisiae.